The present invention relates to a laser measuring method and a laser measuring system, by which a laser beam is projected by rotary irradiation for the purpose of forming a horizontal reference plane or a reference plane tilted with respect to the horizontal reference plane at a predetermined angle and by which it is possible to measure a position by receiving the laser beam.
As a representative system for forming a reference plane by projecting a laser beam by rotary irradiation, a rotary laser system installed at a known point and a photodetection system installed at a measuring point and used for receiving a laser beam from the rotary laser system have been known in the past.
A rotary laser system forms a reference plane by projecting a laser beam with a cross-section of luminous flux in spot-like shape. For instance, when the laser beam is projected in a horizontal plane by rotary irradiation, a horizontal reference plane is formed. When the laser beam is projected within a vertical plane by rotary irradiation, a vertical reference plane is formed. When the laser beam is projected within a tilted plane by rotary irradiation, a tilted reference plane is formed.
The photodetection system comprises a photodetection unit for receiving and detecting a laser beam. Based on the laser beam detected by the photodetection unit, a horizontal reference position, a vertical reference position, etc. are measured.
When measurement as required is performed by projecting a laser beam from a rotary laser system by rotary irradiation, accuracy of installation of the rotary laser system gives direct influence on a measured value. Therefore, it is important to install the rotary laser system at a known point with high accuracy. However, accurate installation requires skill and is difficult to perform. Also, measurement is based on the assumption that the rotary laser system is installed at a known point. Depending on the circumstances, there may be no adequate known point for installing the rotary laser system or there may be environmental condition not suitable for installing the rotary laser system at a known point. In such cases, there has been such problem that measuring operation itself is often difficult to carry out.
When the rotary laser system can be installed, there is no effective method to verify whether the rotary laser system has been accurately installed or not. Further, when the rotary laser system is installed in tilted condition, error may occur with respect to the known point but there has been no effective method to detect such error. Also, when deviation of position occurs due to later cause after the system has been installed, there has been no effective method to detect such deviation.
A laser measuring system is disclosed in JP-A 2002-39755, in which a laser beam is projected by rotary irradiation to form a horizontal reference plane or a reference plane tilted at a predetermined angle with respect to the horizontal reference plane, and by which position can be measured by receiving the laser beam at a photodetection system.